Current color contact-type image sensor devices employ segments of linearly arrayed photosensors produced in silicon and wire bonded as a chip-on-board construction. Each segment is similar or identical in pixel element density. The segments are arranged to span the maximum width of the original image to be scanned. Color images are produced by time-multiplexing illumination produced from at least three different types or colors of LEDs (i.e. red, green, and blue). A self-focusing lens system is arranged to focus the illuminated image on the photosensor pixel elements as the image is mechanically moved across the length of the linear photosensor array.
In order to produce multiple resolution images from the same array, optical elements are required to provide different magnifications of the image onto the photosensor elements. To produce a higher resolution resulting image, an original image of fixed sized must be magnified and focused across a larger number of photosensor elements. Hence, the sensing element ratio must approximately scale with the inverse size ratio of the original image. This multi-resolution sensor and lens configuration is relatively costly to manufacture.
What is needed is an image sensing apparatus which provides multi-resolution color capabilities, but without requiring a complicated lens configuration for magnification. The apparatus should be capable of producing high resolution resulting images from original images which are smaller in size than the full width of the photosensor array. The system should be a relatively compact and economical device to manufacture and use.